Because because class IS a thing. It offers advantages and disadvantages and pretending it doesn't is foolish
I still don't agree with you. Nothing you said is exclusively "middle class".
Kids of working clsss parents go to uni, it's ridiculous to suggest otherwise, working class parents can know people who own companies and have connections. Working clsss parents help their kids onto the property ladder, even if it's by providing a roof over their head whilst they save, or even providing a deposit. Working class does not equate to poor. Middle class does not mean wealthy.
None of what you said is specifically and exclusively class related. There is no I'm middle class so I went to uni or I'm middle class so I had connections that leap frogged me in my career or I'm middle class so my parents helped me onto the properly ladder, those things do and do not happen to people irrelevant of class.
For me, we are all unique. We are not just one big humongous group split into three. Why the need to define yourself?
As I keep saying. You can shout you're working class or middle class till you're blue in the face, it will change nothing about your day to day life, from the job you do, to the pay you get or the house uou live in. It changes nothing. So why do it? Who are you telling? Your friends, your family, your colleagues? Strangers on the internet who would walk past you in the street?
It is totally and utterly irrelevant. An antiquated notion of something that should have died quietly a long time ago and now be laughed about.